At around 10pm officers were called to the incident which took place on the inside lane near ongoing roadworks on the eastbound carriageway between junction 10 and junction 8/9.

The incident was reported to the emergency services by a woman driver involved in the collision.

Paramedics treating the man pronounced him dead at the scene.

The Highways Agency tweeted that two lanes of the M4 remain closed this morning while police investigate. The lanes are not expected to reopen until this afternoon.

Detective Inspector Andy Shearwood investigating said: “It is important that anyone who was driving on that section of the M4 last night – east or westbound – just before 10pm, can recall if they saw anything that may be linked to this incident.

“Did they see a pedestrian? Or a lot of debris in the road? Or anything unusual on the road last night?

“We are trying to establish the exact circumstances of why the man was in the carriageway. At this time it appears that he did not have a broken down vehicle further along the motorway nor was he part of the team carrying out the roadworks.”